Goodwill and Intangibles - Schedule of Gross Carrying Amount and Accumulated Amortization (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 210,596	$ 204,558
Accumulated Amortization	73,711	66,567
Net Book Value	136,885	137,991
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	124,860	121,015
Accumulated Amortization	41,866	38,651
Net Book Value	82,994	82,364
Covenants Not-to-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	12,112	11,807
Accumulated Amortization	5,423	4,773
Net Book Value	6,689	7,034
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	60,024	58,136
Accumulated Amortization	15,089	14,076
Net Book Value	44,935	44,060
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	13,600	13,600
Accumulated Amortization	11,333	9,067
Net Book Value	$ 2,267	$ 4,533